The present invention is related generally to medical devices. More specifically, the present invention is directed to occlusion catheters. Catheters of the present invention incorporate devices and methods allowing a balloon or other occlusion device to be inflated or expanded and remain inflated or expanded while a second catheter is advanced over the proximal end of the occlusion catheter.
Body vessels and conduits, for example coronary arteries, the carotid artery, and lumens of the biliary tree, are frequently treated from within using catheters having means for treating conditions or affected areas at locations within the vessels. Treatment device examples include angioplasty balloons, stents and associated stent delivery catheters, drug delivery catheters, atherectomy devices, and devices for crushing or dissolving blockages in the biliary tree. When using these and other devices, it may be desirable to position and expand an occlusion device such as an inflatable distal occlusion balloon in proximity to the device. In coronary artery applications, the occlusion device can be disposed distally and downstream of the more proximal treatment apparatus such as a rotatable atherectomy burr or an angioplasty balloon. In this application, the occlusion device is a distal occlusion device. A distal occlusion device may also be placed downstream of a stent and associated stent delivery catheter while the stent is being expanded against the vessel wall.
Distal occlusion devices can be used to prevent byproducts of treatment from leaving the treatment area. For example, small particles of plaque may be freed by an atherectomy process. Distal occlusion devices may also be used to provide a quiescent region of a body vessel where treatment can occur. In one example, a coronary artery region may be blocked off from blood flow to allow treating a stenosed region vessel wall with an agent to inhibit restenosis. In another example, a stone may be isolated between a distal and a proximal occlusion balloon, with the space being filled with a chemical to dissolve the stone. In many of these applications, the vessel region proximal of the distal occlusion device is aspirated through a catheter lumen to remove byproducts prior to deflating or removing the distal occlusion device.
An alternative application of an occlusion device is disclosed by Parodi et al. in published PCT Application WO 99/45835. The Parodi et al. disclosure is directed to an occlusion device to guard against embolization during carotid angioplasty. The occlusion device is placed within the vessel lumen proximal to the treatment site, and the device is expandable against the vascular duct to occlude the anterograde blood flow while a vacuum suction device is used to reverse blood flow distal of the occlusion device. The occlusion device includes a mouth for drainage of the retrograde blood flow containing any emboli therein. In this way, the protective device allows the temporary reversal of the flow of blood to prevent emboli from reaching the brain and allows for the drainage of emboli to the outside of the patient""s body. During treatment with an angioplasty balloon distal of the occlusion device, the occlusion device in conjunction with vacuum suction and monitoring of the patient""s blood flow allows controlled reversal of the blood flow.
Inflating an occlusion device is often accomplished in a manner similar to inflating an angioplasty balloon. Proximal manifolds and adapters such as Luer fittings can provide a secure channel between a pressurized fluid supply outside the body and the distal occlusion device such as a balloon. Luer fittings are often bulky and significantly larger than the tubes to which they are attached. Because it may be required to advance a second catheter over the occlusion catheter while the occlusion catheter remains in place, it is generally not possible to advance a second catheter over the occlusion catheter while the conventional fitting is attached. If the conventional fitting were removed from the occlusion device catheter shaft, the distal occlusion device shaft proximal end would require sealing to avoid loss of inflation pressure. The seal itself would have to be small enough to allow the second catheter to pass over the seal while the seal maintained the pressure within the occlusion device and balloon.
Examples of a low profile occlusion device are described by Zadno-Azizi et al. in published PCT application No. WO 99/26692 and by Teitelbaum in U.S. Pat. No. 5,807,330. Both the Zadno-Azizi et al. and Teitelbaum devices never become completely sealed systems during operation. Both devices have proximal ports that must be opened and closed when inflating or deflating the occlusion balloon.
What would be advantageous is an occlusion catheter having a proximal end profile sufficiently small so as to allow a second catheter to be advanced over the proximal end of the occlusion balloon catheter shaft, while maintaining the occlusion balloon in an inflated state. A device allowing inflation and rapid deflation while a catheter is inserted over the distal occlusion catheter would be desirable as well. A device that does not require opening and closing a part to operate the balloon would also be desirable.
The present invention provides occlusion devices for occluding body conduits and vessels. The devices include expandable distal portions and an elongate tubular shaft. The occlusion devices allow other devices to be advanced over and retracted from the occlusion device shafts while the occlusion devices occlude the conduit or vessel. One device includes an elongate tubular shaft having an inflatable occlusion device disposed near the distal end and a lumen extending within the shaft walls. An elongate fluid displacement rod is disposed within the shaft. The fluid displacement rod is preferably at least half the length of the tubular shaft length. The tubular shaft can have a distal fluid preparation portion near the distal balloon for infusing inflation fluid into the shaft prior to use.
In use, the elongate fluid displacement rod can be advanced distally, wherein the volume of the rod within the lumen forces an equal volume of fluid into the distally disposed balloon. The fluid displacement rod can provide precise linear control of the amount of fluid forced into the balloon and a linear relationship between the linear displacement of the rod and the fluid in the balloon. The placement of the rod also provides control of pressure within the balloon. The rod can also provide for rapid inflation of the balloon and rapid deflation of the balloon. Rapid deflation can be advantageous where it is desirable for the occlusion to be ended or reduced rapidly in order to restore fluid flow. One example of this advantage may be found in rapidly deflating a distal occlusion balloon where the balloon is occluding a coronary vessel and patient condition indicates that rapid balloon deflation may be called for.
Another aspect of the invention includes alignment devices for aligning hypodermic needles for insertion into the proximal end of occlusion devices. The hypodermic needle alignment devices are particularly suitable for use with distal occlusion devices having proximally disposed sealable or self-sealing seals.